The introduction of Differentiated Services and other Quality of Service (QoS) methods has necessitated the deployment of several buffers per router output link. Traditionally, router vendors have implemented one, or possibly a few different ways to configure the scheduling between these different buffers for the router. However, this limits the possibilities offered by these technologies to vendor specific solutions and makes it difficult and expensive for operators to modify and update their routers.
Scheduling is an important part of any packet based data network element, such as IP routers. Scheduling is the functionality within the IP routers that decides which queue is served next. Effectively, scheduling decides from which buffer the next transmitted IP packet is picked, which may greatly affect performance.
Recently the increased demand for Quality of Service (QoS) has necessitated new solutions to replace the Best Effort paradigm. For example, Differentiated Services (DiffServ) is a framework standardized by the IETF that is based on the idea of differentiating IP traffic based on QoS requirements. In practice, this means multiple buffers per interface, so that, e.g., delay sensitive traffic can be handled through its own buffers.
The prior art solutions support narrow predefined scheduling schemes. Typically router vendors implement some simple basic schemes and may only allow very limited combinations of the predetermined schemes. This means that when an operator's requirements change, there is a need to upgrade the whole router software to support the change. This may involve, for example, more queues within the router. Effectively, the operator is closely tied with the scheduling model that the router vendor has selected.
From the vendor's point of view the same problem is seen as the need to redesign the scheduling part of IP routers each time that the standards or operators' requirement change. This means extra effort and costs not only for the operator but also for the vendor.
Thus, there is a need for a solution that allows a flexible way to configure the scheduling of IP routers without the need for updating the router software and/or hardware.